Dissecting Escherichia coli Outer Membrane Biogenesis Using Differential Proteomics
Figure 3
AsmA protein abundance and subcellular localization.
PS201 (asmA-SPA lptC+) and PS202 (asmA-SPA araBp-lptC) cells were grown with or without arabinose as indicated. Total membrane protein extracts prepared as described in Materials and Methods were analysed by immunoblotting (panel A) or fractionated by sucrose density gradient (panel B). A) 10 µg of total membrane proteins were loaded in each lane. 55-kDa protein was used as loading control. B) Fractions were collected from the top of the gradient and immunoblotted using antibodies recognizing the 55-kDa protein as IM marker, LamB as OM marker. α-Flag antibodies were used to detect AsmA-SPA protein. wt, PS201; LptC+, PS202 (araBp-lptC) grown under permissive condition (with 0,2% arabinose); LptC-depleted, PS202 grown under non permissive condition (without arabinose).